Comparative demography of two wild cladoceran species, Alona quadrangularis and Scapholeberis mucronata, collected in western Washington state and reared under laboratory conditions

Abstract

Populations of two cladoceran species, Alona quadrangularis and Scapholeberis mucronata, were collected from a pond in Puyallup, Washington, and reared under controlled laboratory conditions. Life tables were developed for each species under the same environmental conditions and feeding regimen to develop basic demographic data. We also compared the major demographic parameters of these two wild species with those of several cladoceran species that are commonly used in laboratory research, Daphnia pulex, D. magna, and Ceriodaphnia dubia. Compared to A. quadrangularis, S. mucronata had a much higher net reproductive rate (R₀), a longer generation time (T), but a similar intrinsic rate of increase (r_m), similar finite rate of increase, similar doubling time (DT), and a lower birth rate (b). Both wild species had lower R₀, shorter T, and higher b than in D. pulex, D. magna, and C. dubia. Results of this study showed that demographic rates differed between A. quadrangularis and S. mucronata, and differed from those reported for the other three laboratory species. These results suggest that data developed for commonly used cladoceran species in the laboratory should not be used to make generalizations about effects on wild species.